%字体大小
\documentclass[UTF8]{ctexart}
\title{the size of the typeface}
\author{LiChao}
\date{June 14.2012}

\begin{document}
\maketitle
\part  {the size is 5pt}
\tiny
hello word!

\part  {the size is 7pt}
\scriptsize
hello world!

\part  {the size is 8pt}
\footnotesize
hello world!

\part  {the size is 9pt}
\small
hello world!

\part  {the size is 10pt}
\normalsize
hello wold!

\part  {the size is 12pt}
\large
hello world!

\part  {the size is 14pt}
\Large
hello world!

\part  {the size is 17pt}
\LARGE
hello world!

\part  {the size is 20pt}
\huge
hello world!

\part  {the size is 25pt}
\Huge
hello world!

\normalsize

the size of typeface is mormal here!
\end{document}